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sound box membrane
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Curt A
- Victor Monarch Special
- Posts: 6851
- Joined: Fri Jul 09, 2010 8:32 pm
- Personal Text: Needle Tins are Addictive
- Location: Belmont, North Carolina
Re: sound box membrane
Where did you get the wooden diaphragm stamping parts?
"The phonograph is not of any commercial value."
Thomas Alva Edison - Comment to his assistant, Samuel Insull.
"No one needs a Victrola XX, a Perfected Graphophone Type G, or whatever you call those noisy things."
My Wife
Thomas Alva Edison - Comment to his assistant, Samuel Insull.
"No one needs a Victrola XX, a Perfected Graphophone Type G, or whatever you call those noisy things."
My Wife
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Inigo
- Victor Monarch
- Posts: 4577
- Joined: Mon Dec 18, 2017 1:51 am
- Personal Text: Keep'em well oiled
- Location: Madrid, Spain
- Contact:
Re: sound box membrane
Yours is a great achievement, but I'd add some comments...
First, the soda can tin is too thick : you'd better try an aluminium sheet from a much thinner material. The aluminium from the food pans used for roast chicken or these prepared foods found in the supermarkets is much thinner (and delicate) and works much better.
Second, the shape of that diaphragm is like the Columbia or Thorens diaphragms. But the back of your soundbox has the shape of an hmv 5 type soundbox. Your diaphragm should have the same concentric corrugations as the back. The principle of these orthophonic soundboxes is having an air chamber of constant thickness, between the diaphragm and the back. You'd better take a mould of the back, filling those three triangular air passages in the center. You'd better look in the web for this, and try to copy it. The most difficult part are the radial or tangential corrugations at the edge, which give the flexibility to the diaphragm to work as a piston. Also you should add a central spider attached to the first big ridge from the center. The spider is who has the central dome with the hole for attac hing the needlebar little fork. This spider can be done from a thin soda can. Observe these images
You see a damaged back side of the diaphragm, but you can see the basic shape following that of the back plate. In the front images you see the spider attached to the diaphragm ridge, and it is the spider which has a dome with a hole in it for soldering the needlebar fork.
Here you have a video of a repair of a 5b soundbox, where he shows the diaphragm
https://youtu.be/sLIOO-34zxU
First, the soda can tin is too thick : you'd better try an aluminium sheet from a much thinner material. The aluminium from the food pans used for roast chicken or these prepared foods found in the supermarkets is much thinner (and delicate) and works much better.
Second, the shape of that diaphragm is like the Columbia or Thorens diaphragms. But the back of your soundbox has the shape of an hmv 5 type soundbox. Your diaphragm should have the same concentric corrugations as the back. The principle of these orthophonic soundboxes is having an air chamber of constant thickness, between the diaphragm and the back. You'd better take a mould of the back, filling those three triangular air passages in the center. You'd better look in the web for this, and try to copy it. The most difficult part are the radial or tangential corrugations at the edge, which give the flexibility to the diaphragm to work as a piston. Also you should add a central spider attached to the first big ridge from the center. The spider is who has the central dome with the hole for attac hing the needlebar little fork. This spider can be done from a thin soda can. Observe these images
- images.jpeg (8.05 KiB) Viewed 791 times
Here you have a video of a repair of a 5b soundbox, where he shows the diaphragm
https://youtu.be/sLIOO-34zxU
Inigo
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Curt A
- Victor Monarch Special
- Posts: 6851
- Joined: Fri Jul 09, 2010 8:32 pm
- Personal Text: Needle Tins are Addictive
- Location: Belmont, North Carolina
Re: sound box membrane
Does anyone make molds of these designs?
"The phonograph is not of any commercial value."
Thomas Alva Edison - Comment to his assistant, Samuel Insull.
"No one needs a Victrola XX, a Perfected Graphophone Type G, or whatever you call those noisy things."
My Wife
Thomas Alva Edison - Comment to his assistant, Samuel Insull.
"No one needs a Victrola XX, a Perfected Graphophone Type G, or whatever you call those noisy things."
My Wife
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Henry
- Victor V
- Posts: 2624
- Joined: Thu Jan 08, 2009 11:01 am
- Location: Allentown, Pennsylvania
Re: sound box membrane
Maybe, maybe not.The true test will be to answer the question "How does it sound?" in the affirmative.Inigo wrote:Yours is a great achievement, but I'd add some comments...
First, the soda can tin is too thick....
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JerryVan
- Victor Monarch Special
- Posts: 6595
- Joined: Mon Aug 24, 2009 3:08 pm
- Location: Southeast MI
Re: sound box membrane
Wow! That's really great work!
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inecik
- Victor Jr
- Posts: 12
- Joined: Wed Apr 10, 2019 4:46 am
Re: sound box membrane
Hi,thanks your interests and best wishes.This is my first try and I will take your recommendations,I have make wooden diaphragm with lathe.I will put on youtube my gramophone sound.